"Breeding-back" aims to restore or immitate extinct animals by selective breeding. This blog provides general information, the facts behind myths and news from various projects.

Wednesday, 11 July 2018

B.p. namadicus: bone material + new artworks

I already did
a couple of posts on the Indian aurochs, Bosprimigeniusnamadicus, the most comprehensive and up-to-date being this one. At
the time of writing that post, the only picture of original material of this
enigmatic subspecies I knew was a drawing of one skull. Thanks
to a Carnivora Forum member I finally came across photo material of a few
specimen. The two upper photos show bulls for certain, I am not sure about the
last one.

The skull material

The crania
show some very interesting morphological differences to the European
subspecies, B. p. primigenius. First
of all, the skulls are definitely narrower than European skulls (the upper one
might still be within the variation range, though) and most zebus tend to have
a very slender face as well. The horns of the known specimen are, as given in
the literature, wide-ranging and considerably longer in proportion than the
average for European skulls (which had, though, regional and chronological
variation). Considering that many
zebuine or zebuine-influenced breeds tend to have large to very large horns,
this might be a basal trait – although the huge horns of, for example, Watussi
and similar breeds have certainly been enhanced by domestication.

There is
also a more precise drawing of the Lydekker skull available on the web, which
also shows it in lateral view. At least this skull seems to have the same 60° horn
orientation as in the average European aurochs.

New Indian aurochs art

Seeing
these photos of original bone material of the Indian aurochs has inspired me to
do some new life illustration of this interesting subclade. As explained in the
post linked above, there are a few traits that can be said with certainty, some
that can be inferred by parsimony and some traits displayed by zebuine cattle
might actually be wildtype traits of the Indian aurochs.

Directly
proven traits:

- smaller
body size, perhaps between 150-160cm for bulls

-
proportionally longer, wide-ranging horns

Traits
inferred by parsimony:

- a more
slanted pelvis than in taurine cattle

- basic
aurochs and wild cattle morphology (long legs, athletic body)

- E+ base colour

Zebuine
traits that might in fact be wildtype traits:

- longer
dewlap than in the European aurochs (functional purpose: thermoregulation)

- zebuine
colour modifiers

Putting
everything together, here is the result:

The head
and horn shape was drawn to match the skull material. I tried to give the face a
kind of zebuine appearance. The body shape is the classic aurochs body shape (I
do not assume any differences in proportions, hump size or other morphological
traits as long there is evidence for). As for the colour, here is were
intuition comes into play. Many zebus show white areas between the forelegs, on
the dewlap and also the underbelly, which is said to be caused by a “zebuine
tipping gene” (it is not specified whether it is an extra locus or just an
allele) and also displayed by other bovine species. I like to illustrate my
namadicus with this trait. Also, zebus tend to have another form of colour
saddle, different from taurine cattle. It is not a true saddle that covers the
upper middle part of the torso, but the sides and often merges fluently into
the “zebu tipping area”. Many zebuine bulls show this trait, and it might just
be a consequence of reduced sexual dimorphism as in taurine bulls, but for this
drawing I assumed it to be a wildtype trait. It is pure speculation, but
intuitively I think it is not an improbable colouration for a tropical bovine,
which tend to be more colourful than boreal ones.

I also did
not give it any curly forelocks. Forelocks are well-proven for the European
subspecies and the wide majority of taurine bulls and also cows have them, yet
no zebuine cattle show curly forelocks. Tropical bovines tend to have skin
flaps and long dewlaps for display, while those in temperate climates tend to
have hairy ornamentation for thermoregulatory reasons, thus I think it is plausible
that Indian aurochs did not posses forelocks but an elongated dewlap instead. In
previous posts I ruled out that the zebuine hump has any function, and
therefore did not assume its presence for Indian aurochs. However, a Carnivora
Forum member pointed out it might have had a display function in the wildtype,
just as the enlarged processus spinosi have in Gaur and Banteng. This is very
speculative, however, and probably only prehistoric art could provide a clue.

Being
motivated by my new Indian aurochs bull portrait, I could not hesitate to do a
table of bulls of all three aurochs subspecies along with their domestic
descendants.

As there is
only evidence for black aurochs bulls in Europe, I gave the primigenius bull a solid black back.
However, for the African aurochs, there is evidence from at least two artworks
that at least some bulls of this subspecies had a colour saddle (see here). So
the colouration of the African bull is not as speculative as that of the Indian
bull. It might as well be possible that all three geographical variants had a
solid black colour like the European one. As there are no morphological
differences between the African and European aurochs noted in the literature, the
African and the European aurochs are actually the same drawing, only the
colouration is different. The subspecies that sticks out is the Indian one,
which is not surprising considering that the lineages of taurine cattle and
zebuine cattle, and thus B.p. primigenius
and B.p. namadicus, separated 1,7-2
million years ago[1], which is considerably longer than between Przewalski’s
and domestic horses, for example. Here is a close-up for the Indian aurochs
alone:

I think the
drawing does look plausible for the wildtype of a bull like this one down
below.

Something
interesting that I noticed is that the size difference between all five bovines
is not that huge, especially not between the wildtypes and their domestic derivatives.
I drew them to the same scale. For the European aurochs, I chose a size of
170cm at the withers, for the African 160cm and for the Indian aurochs 150cm
(which is, by the way, the lower size limit for European mainland bulls). The
taurine bull has a height of 140cm, the zebu about 135cm. But the size
difference does not appear that large. I think the reason for that is that
withers height is not the most reliable measure for this comparison, as it is
dependent on the size of the hump i.e. the length of the processus spinosi,
actually. In very derived taurine bulls and most zebu the height of the spine
does not surpass that of the shoulder blade, thus a domestic bull with a
withers height of 150cm would have a larger body than an aurochs of the same
withers height, especially considering that they are more elongated in build.
So what is actually better comparable is the height of the shoulder blade. The
question is, how much higher is the actual height of the shoulder blade of
aurochs compared to cattle? Is it due to scaling or is the size difference
between aurochs and cattle not that large in the end? The best way to evaluate
that would be to compare a skeleton of a grown aurochs bull to that of a
domestic bull in real next to each other. But considering that heavy bulls of
domestic breeds can easily exceed 1000kg living weight while estimations for
aurochs bulls are about 700kg(by Cis
van Vuure, I have reasons to believe they might have been actually 100-200kg
heavier, but more on that in an upcoming post) it might not be that improbable.
Surely, some aurochs individuals truly were huge by cattle standards as there
are skulls of European aurochs with a length of more than 90cm.

In any way,
I did an animated GIF of a the European aurochs and the taurine bull at the
same withers height – it is obvious that the taurine bull has a way larger body
due to the low processus spinosi and the elongated trunk. Even the head would have
the same size. A taurine bull with a shoulder height of 170cm would have a
weight of about 1700-1800kg, which is twice as much as what is estimated for an
aurochs bull of that size.

“Breeding-back” with zebus, once again

In all my
previous posts on the Indian aurochs, I introduced the idea of “breeding-back”
with zebus. India is full of zebu landraces that are not well-known elsewhere but
would be suitable for such a project as they have a slender, squarely-built
body with long legs and long snouts. These include Kenkatha, Malvi, Ponwar,
Haryana, Khilari or the large-horned Gudjerat. Such indigeneous zebus could be
crossed with Watussi for the horn size and curvature and miniature zebus for
the aurochs-like colour and dichromatism. Both Watussi and miniature zebu have
taurine introgression, but as we know from “breeding-back” with taurine cattle,
it is impossible to keep the taurus and indicus lineage 100% separated and it
is the contributed traits that count, not pedigree. While the morphology and
external appearance of the European aurochs is well-known and breeding with its
descendants can approach most of its traits rather well, the life appearance of
the Indian subspecies is far less well-known and zebus seem to be a bit more
removed from their ancestor than taurine cattle. At least, there are no truly
overall primitive zebuine breeds. However, breeding with the zebuine cattle
listed above can produce a population that resembles namadicus in horn shape
and size, proportions, skull shape and probably also colour. Most interesting
would be to release them in a reserve and let them live for themselves for a
number of generations. Heck cattle in Oostvaardersplassen underwent
morphological changes after a mere 30 years of natural reproduction (see here,
here or here) and it is likely that these zebu would experience something
similar. These changes would be functional and evolutionary advantageous as
they are the result of natural selection. Therefore, it would be interesting
what happens to the shoulder- and neck region of the cattle. In
Oostvaardersplassen, Heck cattle developed a tendency to have a stronger
shoulder region including the typical hump of wild bovines with elongated
shoulder spines that support larger neck- and shoulder muscles which are needed
during combat. In zebuine bulls, the neck muscles seem somewhat weaker which
might be a consequence of the fleshy zebuine hump which is caused by a
hypertrophied M. rhomboideus. Thus, a bull with a zebuine hump might be in
disadvantage compared to such with a wild cattle-like shoulder morphology. If,
after a couple of generations, the zebuine hump would indeed disappear and they
would develop a wild cattle-like hump like Heck cattle at OVP, it would be a
strong hint that the fleshy zebuine hump is an artefact of domestication and
was not present in namadicus as it is not functional. If, however, zebus do
indeed use it for display, head-to-head combat might play a lesser role in
their social life than in taurine cattle, and it might remain. This can only be
demonstrated by executing such a zebu dedomestication experiment.

3 comments:

The Zebu hump also has fatty deposits within its hypertrophied muscular matrix; actually, in the zebus of the Madagascar, which have the smallest humps of any zebus I know of, the hump is almost entirely fat and has very little muscular development. Considering that the volume of fat in the hump shrinks as zebus lose condition, It seems as if these deposits actually function as a store of energy to be used in times of energetic deficiency. Since the Indian Aurochs was xerophyllic, I think the possible energy storing capacity of the hump, like in camels, is at least as plausible a line of conjecture as its possible use as a display structure.

Do you have literature on zebu humps composed of mainly fat? I have only found such claiming that it is composed of muscle exclusively (it should of course have some subcutaneous fat tissue as elsewhere on the body).

About this blog

This blog is on everything related to the so-called “breeding-back” of extinct animals: From the extinct animals themselves, over their often domestic descendants and dedomestication to news and facts about various breeding-back projects, reports and photos from my own breeding-back related trips. I try to have a balanced and fact-based approach to this subject and to dismantle many of the popular myths. Enjoy!

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About me

My major interest always have been extinct animals, from dinosaurs to Pleistocene megafauna and more recent extinctions. Besides that I am interested in evolution, genetics and ecology.
I am also an amateur animal artist, making drawings and models mostly of extinct animals.